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of TPHg at 97000 ppb. which is lower than 118000 ppb.of the last sampling event.The groundwater hydraulic gradient was calculated at S=0.002 with the down slope in the easterly,direction, which • matches the historical data for this site. The gradient is determined by the first ground water elevation data of MW-1, MW-2, and MW-3 (see a site map attached). Analysis for oxygenates during this event indicate the presence of both MTBE and 1,2 DCA in moderate amounts in MW-1,MW-2,MW-7S,MW-8S. EW-1 had the highest concentration ofboth MTBE at 620 ppb.,1,2 DCA at 370 ppb and EDB at 370 ppb. (see attached recap sheets). The monitoring wells that were damaged by others were purged and sampled.Monitoring well MW- 8S appears to have been impacted by the damage. TPHg has jumped from non-detect on 8117102 , to 5730 ppb on the last event,than lowered to 828 ppb during this event. This is most likely a result of the damage to this casing. Conclusions In general, all of the monitoring well groundwater samples and the sample from EW-1, yielded lower concentrations of TPHg than last quarter. The lone exception is MW-6. The MW-1 groundwater sample results were lower in concentrations than last years second quarter monitoring event. MTBE was detected in MW-1,MW-1R, MW-2 and EW-1.Low concentrations of 1,2-DCA were detected in MW-1, MW-1R, MW-2, MW-3, MW-5, MW-7S, MW-8S, and EW-1. Low concentrations of EDB were analyzed in MW-land MW-1R. EW-I produced EDB at 370 ppb. The extraction well EW-1 produced the highest concentrations of TPHg, 1,2 DCA and EDB and is positioned in the best location to remove the highest concentrations of gasoline contamination in the sand aquifer at 50'below the surface. Recommendations The author recommends that monitoring well sampling be continued on a quarterly basis with analysis for TPHg,BTEX,and oxygenates.MW-8S should be purged at double the standard amount again for the next sampling event. Work in Progress The present work plan calls for mobilization of a 21,000 gallon tank and pump installation for the pump test. This work will be started when the UST Fund is current on reimbursement for this site. At the present time, funds for the completion of this work plan are not available. Please contact Ervin Rifenburg of this office at (209)368-9381 if you have any questions on this report. Respectfully submitte OfEsSith, Foo igine ne h�. ��{. }, +i+ 97 Up. Ervin en , P a Attachment : Groundwater` s Recap, Site Maps, Del-Tech Monitoring Report,Lab Reports cc: Michael D. & Sharon 4livarez, 436 W. Scotts Ave. Stockton, Ca. 3